Meshing gear apparatus for making heat exchangers



Aug. 26, 1969 H J. LOEHLEIN ETAL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEKT EXCHANGERS 8 Sheets-Sheet 1Original Filed Dec. 23, 1963 FIGJ FIG.3

INVENTORS HAROLD J.LDEHLE|N EDWARD E. CURRAN y mam ATTd RwEYs Aug. 26,1969 H J. LOEHLEIN ET AL 3,462,990

MESHING GEAR APPARATUS FOR- MAKING HEAT EXCHANGERS Original Filed Dec.23, 1963 8 Sheets-Sheet z INVENTORS {Z k? ssmaag E-z u s'ksr 6 BY (.47vf r I," z

THEIR ATTORNEYS Aug. 26, 1969 H J. LOEHLEIN E AL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS 8 Sheets-Sheet 5Original Filed Dec. 23, 1963 FIGS Aug. 26, 1969 H LOEHLEIN E L 3,462,990

mn'snnm GEAR APPARATUS FOR MAKING HEAT EXCHA'NGERS Original Filed Dec.23, 1963 a Sheets-Shet 4 INVENTORS HAROLD J. LOEHLElN EDWARD E.CURRAN HJ. LQEHLEIN ETAL MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERSOriginal Filed Dec. 23, '1963 8 Sheets-Sheet 5 rab IN VENTORS HAROLD J.LOEHLEIN EDWARD E.CURRAN Fuenmam ATT6RNEY$ Aug. 26, 969 H J. LOEHLEIN ETAL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS original Filed Dec.23, 1963 8 Sheets-Sheet 6 l N VENTORS HAROLD J. LOEHLEIN F G EDWARDECURRAN BY Mm, n44

x THEIR ATTORNEYS Aug. 26, 1969 H J LQEHLEIN ETAL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS 8 Sheets-Sheet 7Original Filed Dec. 23, 19 3 FIG.25

INVENTORS N 1 W EN 5 n E mm n/m m A T w W v n MWM m wR M E 0A m RW AD 2EL Aug. 26, 1969 H J, LQEHLE|N ET AL 3,462,990

MESHING GEAR APPARATUS FOR MAKING HEAT EXCHANGERS Original Filed Dec.23, 1963 8 Sheets-Sheet 8 INVENTORS HAROLD J. LOEHLEIN EDWARD E. CURRANTHEIR ATTORNEYS 3,462,990 MESHING GEAR APPARATUS FOR MAKING HEATEXCHANGERS Harold J. Loehlein, Richmond, Va., and Edward E. Curran,Louisville, Ky., assignors to Reynolds Metals Company, Richmond, Va., acorporation of Delaware Original application Dec. 23, 1963, Ser. No.332,818, now Patent No. 3,294,162, dated Dec. 27, 1966. Divided and thisapplication Oct. 6, 1966, Ser. No. 584,712

Int. Cl. B21d 13/00, 13/04 US. Cl. 72-186 22 Claims ABSTRACT OF THEDISCLOSURE Meshing gear members have teeth adapted to cooperatively actupon a flange of a tubular workpiece so as to divide it to form fins,twist the fins, and draw and iron the fins, thereby increasing theirsurface area while decreasing their thicknesses.

This application is a divisional patent application of its copendingparent patent application, Ser. No. 332,818, filed Dec. 23, 1963, nowPatent No. 3,294,162.

This invention relates to an improved heat exchanger construction or thelike as well as to improved methods and apparatus for making such a heatexchanger or the like.

It is well known that heat exchangers can be formed of a hollow tubularmember through which a cooling or heating medium is circulated wherebythe outer peripheral wall of the hollow tubular member forms the primaryheat exchanger surface for heat transfer purposes.

In order to increase the heat transfer between the surroundingatmosphere and the circulating medium, various manufacturers provide finmeans to be attached to the outer peripheral surface of the hollowtubular member to increase the surface area of the heat exchangerstructure, the fins each forming what is commonly known as a secondaryheat exchanger surface.

However, it has been found that the fins forming the secondary heatexchanger surfaces of the heat exchanger must be intimately placed incontact with the primary heat exchanger surface in order for the same tobe effective whereby many manufacturing problems are encountered.

According to the teachings of this invention, such secondary heatexchanger surface is uniquely provided whereby the secondary heatexchanger surface is formed integrally with the primary heat exchangersurface in such a manner that an effective heat exchanger constructionis provided.

In particular, one type of heat exchanger structure of this invention isprovided by extruding a hollow tubular member from metallic material,such as aluminumcontaining metallic material or the like, with thehollow tubular member having an outwardly directed flange integrallyinterconnected thereto and substantially radiating from the longitudinalaxis of the hollow tubular member.

Thereafter, the flange of the hollow tubular member is divided into aplurality of fins each having its surface area substantially increasedover the surface area of the part of the flange from which therespective fin has been formed whereby an effective heat exchangerconstruction is provided in a rapid and simple manner,

As will be apparent hereinafter, the heat exchanger construction of thisinvention can be utilized in many applications for the transfer of heatin a simple and effective manner heretofore unobtainable by well knownheat nited States Patent O 3,462,999 Patented Aug. 26, 1969 iceexchanger constructions whereby the heat exchanger constructions of thisinvention are relatively inexpensive.

Accordingly, it is an object of this invention to provide an improvedheat exchanger construction having one or more of the novel features ofthis invention as set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved method formaking such a heat exchanger construction or the like.

A further object of this invention is to provide an improved apparatusfor making such a heat exchanger construction or the like.

Other objects, uses and advantatges of this invention are apparent froma reading of this description which proceeds with reference to theaccompanying drawings forming a part thereof and wherein:

FIGURE 1 is a perspective View illustrating one embodiment of the heatexchanger blank of this invention.

FIGURE 2 is a view similar to FIGURE 1 and illustrates anotherembodiment of the heat exchanger blank of this invention.

FIGURE 3 is a schematic, fragmentary, perspective view illustrating themethod and apparatus for converting the blank of FIGURE 1 or 2 into theheat exchanger construction of this invention.

FIGURE 4 is an end view of the method and apparatus illustrated inFIGURE 3.

FIGURE 5 is a front view of one of the gear means of the apparatus ofthis invention.

FIGURE 6 is a cross-sectional view taken on lines 6-6 of FIGURE 5.

FIGURE 7 is a fragmentary, cross-sectional view taken in line 7-7 ofFIGURE 6.

FIGURE 8 is a fragmentary, end view illustrating how the apparatus ofFIGURE 3 forms the heat exchanger construction of this invention.

FIGURE 9 is a top view of the heat exchanger construction of thisinvention.

FIGURE 10 is a side view of the heat exchanger construction illustratedin FIGURE 9.

FIGURE 11 is a fragmentary, cross-sectional view taken on line 11-11 ofFIGURE 10.

FIGURE 12 is a top plan view of an improved heat exchanger constructionformed according to the teachings of this invention.

FIGURE 13 is a fragmentary, cross-sectional view taken on line 13-13 ofFIGURE 12.

FIGURE 14 is a fragmentary, cross-sectional view taken on line 14-14 ofFIGURE 13.

FIGURE 15 is a view similar to FIGURE 14 and illustrates the framemember of this invention before the same has been attached to the heatexchanger tube construction.

FIGURE 16 is a top plan view of another heat exchanger construction ofthis invention.

FIGURE 17 is a fragmentary, cross-sectional view taken on line 1717 ofFIGURE 16.

FIGURE 18 is a fragmentary, cross-sectional view illustrating oneapplication of the heat exchanger c011- struction of this invention.

FIGURE 19 is a cross-sectional view taken on line 19-19 of FIGURE 18.

FIGURE 20 is a fragmentary, cross-sectional view of the heat exchangertube construction of this invention.

FIGURE 21 is a plan view of a house or the like.

FIGURE 22 is a fragmentary, enlarged, cross-sectional perspective viewtaken on line 22-22 of FIGURE 21.

FIGURE 23 is a cross-sectional view illustrating the heat exchangerconstruction of this invention in another application thereof.

FIGURE 24 is a cross-sectional view taken on line 2424 of FIGURE 23.

FIGURE 25 is a cross-sectional view of a domestic refrigerator or thelike utilizing a heat exchanger construction of this invention.

FIGURE 26 illustrates another embodiment of this invention which can beutilized in the refrigerator of FIG- URE 25.

FIGURE 27 is an exploded perspective view of the parts illustrated inFIGURE 26.

FIGURE 28 illustrates another application of the heat exchangerconstruction of this invention.

FIGURE 29 is a cross-sectional view illustrating another application ofthe heat exchanger construction of this invention.

FIGURE 30 is a perspective schematic view of the structure illustratedin FIGURE 29.

FIGURE 31 is a fragmentary perspective view of another heat exchangerconstruction of this invention.

FIGURES 32 and 33 are views similar to FIGURE 31 and illustrate otherembodiments of this invention.

FIGURE 34 is a view similar to FIGURE 8 and illustrates anotherembodiment of this invention.

While the various features of this invention are hereinafter describedand illustrated as being particularly adaptable for forming a heatexchanger construction or the like, it is to be understood that thevarious features of this invention can be utilized singly or in anycombination thereof to provide other constructions as desired.

Therefore, this invention is not to be limited only to the embodimentsillustrated in the drawings, because the drawings are merely utilized toillustrate one of the wide variety of uses of this invention.

Referring now to FIGURE 1, the improved heat exchanger blank of thisinvention is generally indicated by the reference numeral 40 andcomprises an elongated hollow tubular member 41 having one or moreoutwardly directed flanges 42 integrally interconnected to the outerperipheral surface 43 of the hollow tubular member 41.

While the heat exchanger blank 40 of this invention can be formed in anysuitable manner and of any suitable material, the embodiment illustratedin FIGURE 1 is formed by extending metallic material, such asaluminumcontaining metallic material or the like, by a conventionalextruding apparatus 44 in a conventional manner.

Thus, it can be seen that the heat exchanger blank 40 of this inventioncan be extruded in a simple and effective manner to provide a heatexchanger having the desired length in a manner hereinafter set forth.

Further, while the heat exchanger blank 40' of this invention can haveany suitable dimensions, the embodiment thereof illustrated in thedrawing has the outside diameter of the hollow tubular member 41approximately of an inch while the thickness of each flange 42 isapproximately 0.035 of an inch, the width of the flanges 42 being anydesired width.

However, it is to be understood that the above dimensions and materialsfor forming the heat exchanger blank 40 of this invention are not alimitation on this invention as the same can vary as desired.

While the flanges 42 of the heat exchanger blank 40 of this inventionare of uniform thickness throughout the length thereof, it is to beunderstood that the same can have a varying thickness throughout thelength thereof, if desired.

For example, reference is made to FIGURE 2 wherein another heatexchanger blank is generally indicated by the reference numeral 40A andparts thereof similar to the heat exchanger blank 40 are indicated bylike reference numerals followed by the reference letter A.

As illustrated in FIGURE 2, the flanges 42A extending outwardly from thehollow tubular member 41A respectively taper from the outer peripheralsurface 43A of the hollow tubular member 41A to the outer free edges ofthe flanges 42A.

For example, should the outer tubular member 41A have an outsidediameter of approximately /8 of an inch, the flanges 42 can beapproximately 0.035 inch at the outer peripheral surface 43A of thehollow tubular member 41A and tapered downwardly to approximately 0.020inch at the outer free ends thereof.

Therefore, it can be seen that the heat exchanger blanks and 46A of thisinvention can vary in the configuration thereof while still beingadapted to form the heat exchanger constructions of this invention in amanner hereinafter set forth.

Therefore, since either the heat exchanger blank 40 or heat exchangerblank 40A can be utilized in the manner hereinafter described, only theheat exchanger blank 40 will be specifically referred to with theunderstanding being that the same description would apply to the heatexchanger blank 40A, if desired.

While the heat exchanger blanks 40 and 40A of this inventionrespectively have two diamtrically opposed flanges 42 extending from thetubular member 41 or 41A, it is to be understood that the variousfeatures of this invention can be utilized with the hollow tubularmember 41 or 41A having one or any desired number of flanges 42 disposedin any desired relationship about the outer peripheral surface 43 or 43Athereof whereby this invention is not to be limited to a heat exchangerconstruction having just two flanges 42 or 42A as will be apparenthereinafter.

After the blank 40 has been formed in the above manner, the same has theflanges 42 thereof divided into a plurality of fins integrallyinterconnected to the hollow tubular member 41 to provide a uniquesecondary heat exchanger surface for the hollow tubular member 41, thefins each being formed from the flanges 42 and having the surface areathereof substantially increased over the part of the flange 42 fromwhich the respective fin is formed in the manner now to be described.

Reference is now made to FIGURE 3 wherein an improved method andapparatus of this invention is generally indicated by the referencenumeral 45 and is utilized to form the flanges 42 of the hollow tubularmember 41 into a plurality of heat exchanger fins 46 integrallyinterconnected to the hollow tubular member 41 to provide a secondaryheat exchanger surface therefor, each end 46 being formed from a part ofthe flange 42 and having the surface area thereof substantiallyincreased over the original surface area of the part of the flange 42from which the respective fin 46 is formed.

While the apparatus 45 illustrated in FIGURE 3 indicates that only oneflange means 42 of the hollow tubular member 41 is being converted intofins 46, it is to be understood that the apparatus 45 of this inventioncan simultaneously form the fins 46 from the opposed flanges 42 of thehollow tubular member 41 in the manner illustrated in FIGURE 4.

The apparatus 45 comprises a pair of gear means 47 and 48 cooperating ina manner hereinafter described to operate on one flange means 42 of thehollow tubular member 41 and to rapidly and effectively convert theflange means '42 into the plurality of fins 46 in the manner illustratedin FIGURE 8 and which will be hereinafter described.

As illustrated in FIGURES 5-7, each gear means 47 and 48 issubstantially identical to each other except that the gear means 47 hasthe teeth thereof pointing in one direction as illustrated in FIGURE 8while the like teeth on the gear means 48 point in the oppositedirection as illustrated in FIGURE 8 to perform the function of thisinvention.

Therefore, the gear means 48 will be described and illustrated inFIGURES 5-7 with the understanding that the gear means 47 is formed inthe same manner except that the teeth thereof point in the oppositedirection.

As illustrated in FIGURES 57 the gear means 48 includes a hub 49 havinga cylindrical bore 50 passing therethrough to permit the gear means 49to be fastened onto a suitable shaft by threaded members passing throughthreaded bores 51 formed in the hub 49.

The hub 49 of the gear means 48 has a plurality of teeth 52 radiatingoutwardly therefrom with each tooth 52 having a substantially arcuateleading surface 53 when the gear means 48 rotates in a clockwise mannerin FIG- URE 5 while the trailing side 54 of the tooth 52 issubstantially straight as illustrated in FIGURE 5.

As illustrated in FIGURE 8, each tooth 52 of the gear means 48 has asubstantially flat outer end or land 55 which cooperates with thestraight side 54 thereof to define a shearing edge 56 for a purposehereinafter described. The leading side 53 of each tooth 52 of the gearwheel 48 curves arcuately from the point 57 to approximately the point58 whereby the remainder of the surface 53 is substantially straight andparallel to the surface 54 until the surface 53 joins the hub 49 of thegear means 48. correspondingly, each tooth 52 of gear means 47 has aleading surface 53, a trailing surface 54', a land 55, and a shearingedge 56'. The teeth 52 of the respective gears 47 and 48 are shaped sothat they mesh to define a working depth or depth of engagement Wsubstantially greater than the tooth thicknesses T at the working depthboundary nearest the tooth root, thereby providing for substantialrelative traversing movement between said surfaces while said surfacesare adjacent each other.

As illustrated in FIGURE 6, each tooth 52 of the gear means 48 has afront side 59 which will be disposed in zone 59a adjacent the hollowtubular member 41 while the opposed side 590 of the tooth 52 will beremote from the hollow tubular member 41. The side 59 of each tooth 52of the gear means 48 is arcuate, the land 55 gradually curving towardthe axis of that gear means, in the manner illustrated in FIGURE '6while the side 59c thereof is substantially straight. As is shown 'byFIGURES 6 and 8, the radius of curvature of the land 55 of each tooth 52at its side 59 corresponds to the tooths working depth.

Further each tooth 52 of the gear means 48 at the side 59 thereof isrounded or arcuate in the manner illustrated in FIGURE 7.

This particular configuration of the teeth '52 of the gear means 47 and48 form the fins 46 from the flange 42 of the hollow tubular member 41in a unique manner now to be described.

As illustrated in FIGURE 8, the gear means 47 is rotating in acounterclockwise direction while the gear means 48 is rotating in aclockwise direction so that the teeth 52 thereof mesh in the mannerillustrated in FIG- URE 8, the flange 42 of the hollow tubular member 41either being passed through the nip of the rotating gear means 47 and 48from left to right in the manner illustrated in FIGURE 8 or the gearmeans 47 and 48 can be moved from right to left while the hollow tubularmember 41 is being held stationary even though the gear means 47 and 48are rotating in the manner indicated by the arrows in FIGURE 8.

In any event, it can be seen that as the gear means 47 and 48 rotate,the teeth 52 on the gear means 47 begin to bend the flange 42 of thehollow tubular member 41 downwardly as represented by the gear teeth 52aand 52b in FIGURE 8. However, since the teeth 52a and 52b are arcuate atthe surface 59 thereof as illustrated in FIG- URE 6, the portion of theflange 42 adjacent the hollow tubular member 41 is not bent downwardlyas illustrated in FIGURE 8.

As the tooth 520 of the gear means 48 begins to move upwardly betweenthe teeth 52b and 52d of the gear means 47 in the manner illustrated inFIGURE 8, it can be seen that the tooth 52c begins to move the flange 42upwardly between the teeth 52b and 52d while utilizing the edge 56thereof to cooperate with the edge 56 and surface 54 of the gear tooth52b to shear the flange 42 into a particular fin 46a.

As the gears 47 and 48 continue to rotate, it can be seen that the lowerportion of each sheared fin 46 is drawn and ironed by the cooperatingsurfaces 53 on the adjacent teeth 52 of the gear means 47 and 48.

For example, it can be seen that the teeth 52e and 52f in FIGURE 8 aredrawing and ironing the lower portion of the fin 46b to substantiallyelongate the same while the land 55 of the tooth 52e is moving the upperportion of the fin 46b back to a coplanar relation with the point ofattachment of the fin 46b to the hollow tubular member 41.

As the gear teeth 52 of the gear means 47 and 48 pass through theirfully meshed relation, it can be seen that the surfaces 53 of adjacentteeth 52 thereof cooperate together to draw and iron the top portion ofeach fin 46 to further elongate and substantially curve the same wherebythe resulting fin 46 has a substantially S-shaped crossscctionalconfiguration.

For example, see FIGURE 8 wherein the gear teeth 52g and 52h of the gearmeans 48 and 47 respectively begin to draw and iron the top portion ofthe fin 462.

Thus, it can be seen that as the flange 42 of the hollow tubular member41 is passed through the nip of the meshing gear means 47 and 48, theteeth 52 on the gear means 47 and 48 cooperate together to shear anddivide the flange 42 into individual fins 46 while at the same timedrawing and ironing the fins 46 to substantially increase the surfaceareas thereof over the surface areas of the parts of the flange 42 fromwhich the respective fins 46 are formed whereby the fins 46 provide aneffective secondary heat exchanger surface for the resulting heatexchanger construction 60 illustrated in FIGURE 9.

As previously set forth, the apparatus 45 of this invention can comprisemerely a pair of gear means 47 and 48 which will operate on a singleflange 42 of the hollow tubular member 41 or can comprise four gearmeans as illustarted in FIGURE 4 for simultaneously operating on theopposed flange means 42 of the hollow tubular member 41 to form the heatexchanger construction 60.

In any event, the gear means of the apparatus 45 of this invention soform the fins 46 in the manner illustrated in FIGURES 9-11 that each fin46 is integrally joined to the outer peripheral surface 43 of the hollowtubular member 41 by opposed gusset shaped portions 61 and 62 asillustrated in the top view of FIGURE 9 to not only increase thestrength or the particular fin 46 but to increase the surface contactthereof with the hollow tubular member 41 to promote the heat transferin a manner well known in the hear exchanger art.

Such gusset portions '61 and 62 for each fin 46 are formed by having thesurfaces 59 of the teeth 52 of the gear means 47 and 48 formed arcuatelyin the manner illustrated in FIGURE 7.

Further, each fin 46 has an inner portion 63 as illustrated in FIGURES10 and 11 that curves arcuately and is joined to the remainder of theflange 42 to provide not only a structural relationship therewith, butalso to increase the surface contact between the particular fin 46 andthe outer peripheral surface 43 of the hollow tubular member 41.

Thus, it can be seen that the apparatus and method of this invention asillustrated in FIGURE 5 effectively divide the flange or flanges 42 ofthe hollow tubular member 41 into secondary heat exchanger surfacescomprising a plurality of fins 46 each having a surface areasubstantially increased over the surface area of the part of the flange42 from which the respective fin 46 was formed.

For example, it has been found that the surface area of each fin 46 canbe increased from at least 20% to over of the original surface area ofthe part of the flange 42 from which the respective fin 46 has beenformed.

Thus, not only has the surface area of the fins 46 been increased in theabove manner, but also the fins 46 are integrally interconnected to theouter peripheral surface 43 of the outer tubular member 41 whereby themost intimate contact is provided between the fins 46 and the hollowtubular member 41 to provide the heat transfer relationship required ina heat exchanger construction.

In addition, the fins 46 are so joined to the hollow tubular member 41that the same are structurally attached thereto even though the samehave been rendered relatively thin by the previously described drawingand ironing operation.

Thus, the apparatus and method of this invention effectively and simplyform the heat exchanger construction 60 of this invention wherein theheat exchanger construction 60 has the advantages previously set forth.

After the desired length of the heat exchanger blank 40 has been formedinto the heat exchanger construction 60, the heat exchanger construction60 can be bent, coiled, spiraled, or remain straight for storage andshipment thereof for being formed into a particular configuration for aparticular application thereof, the heat exchanger construction 60 ofthis invention being readily adaptable for most applications wherein aheat exchanger construction is needed.

For example, the heat exchanger construction 60 previously described canbe sinuously bent in the manner illustrated in FIGURES 1215 to formanother type of heat exchanger construction of this invention which isgenerally indicated by the reference numeral 64, the heat exchangerconstruction 64 being particularly adaptable as being utilized as anevaporator or condenser, as desired.

As illustrated in FIGURE 12, the heat exchaner construction 60 has beenbent in a sinuous manner so that the same defines a substantiallyrectangular construction having elbows 65 at the opposed side of therectangular construction and interconnecting together adjacent straightlengths 66 of the hollow tubular member 41, the hollow tubular member 41being provided with its own inlet 67 and outlet 68 as illustrated inFIGURE 12.

If desired, the fins 46 on the hollow tubular member 41 can be removedin the region of the elbows 65 thereof as well as on the inlet 67 andoutlet 68 thereof as illustrated in FIGURE 12.

In order to provide a rigid mounting construction for the sinuously benttubular member 41, a pair of opposed frame members 69 are provided atthe elbows 65 of the hollow tubular members 41 and attached thereto in amanner now to be described.

For example, each frame member 69 can comprise a lower portion 70 and anupper portion 71 defining a plurality of slots 72 therebetween whichrespectively receive the elbows 65 in the manner illustrated in FIGURE15.

Therefore, it can be seen that each frame member 69 can be slipped ontothe elbows 65 at one of the opposed sides of the sinuously bent hollowtubular member 41 with the elbows 65 being readily received and passingthrough the slots 72 therein.

Thereafter, the upper portions 71 of the frame member 69 are deformeddownwardly in the manner illustrated in FIGURES 13 and 14 to effectivelyinterlock the elbows 65 thereto without utilizing fastening members orthe like whereby the frame members 69 provide a rigid unit with thehollow tubular member 41 and permit the same to be readily mounted inany desired relationship by mounting means 73 on the frame members 69.

Another type of heat exchanger construction of this invention can beformed from the structure 60 illustrated in FIGURE 9 to provide anevaporator, condenser or the like in a manner similar to the heatexchanger construction 64 previously described, reference being made toFIGURES 16 and 17 wherein another heat exchanger construction of thisinvention is generally indicated by the reference numeral 74.

As illustrated in FIGURES 16 and 17, the hollow tubular member 41previously described is sinuously and substantially spirally wound orcoiled in the manner illustrated in FIGURE 16 to define a substantiallyrectangular construction having elbows 75 at the opposed sides thereofand respectively interconnecting together adjacent 8 lengths 76 and 77of the hollow tubular member 41, the hollow tubular member 41 having aninlet 78 and outlet 79 at the opposed ends thereof.

The coiled tubular member 41 is adapted to be formed into a rigid unitby a pair of opposed frame members 80 respectively interconnected to theelbows 75 of the bent tubular member 41.

For example, each frame member 80 can comprise a substantially U-shapedportion 81 in the manner illustrated in FIGURE 17 disposed against theoutside of each elbow 75 at one side of the rectangular construction anda substantially cylindrical bar or portion 82 respectively passingthrough the elbows 75 in the manner illustrated in FIGURE 17 anddetachably secured to the portion 81 by a plurality of threadedfastening members 83.

Thus, it can be seen that in the heat exchanger construction 74illustrated in FIGURES l6 and 17, the fins 46 on the hollow tubularmember 41 need not be removed in the region of the elbow 75 thereof, ifdesired, as the portions 82 of the frame members 80 eifectivelyinterconnect the frame members 80 to the elbows 75, the inlet 78 andoutlet 79 of the hollow tubular member passing effectively throughsuitable apertures formed in the portion 81 thereof as illustrated.

Therefore, it can be seen that unique heat exchanger constructions canbe provided from the finned tubular member 41 of this invention toprovide the desired heat exchanger function.

While the heat exchanger constructions 64 and 74 of this invention areparticularly adaptable for forming evaporators or condensers forrefrigerating systems or the like, it is to be understood that the samecan be utilized in other places where heat exchanger structures arerequired.

For example, reference is made to FIGURE 25 wherein a domesticrefrigerator 84 is provided and has the conventional non-frozen foodcompartment 85 and the conventional frozen food compartment 86respectively cooled by an evaporator 87 having air forced across thesame by a suitable fan 88. Thus, the heat exchanger constructions 64 and74 of this invention are particularly adaptable for forming the heatexchanger construction 87 illustrated in FIGURE 25.

Thus, it can be seen that the finned tubular member 41 of this inventionhas many uses in the heat exchanger field and the same lends itself toparticular configurations for particular heat exchanger applications.

For example, reference is made to FIGURE 18 wherein the finned tube 41of this invention is disposed in spiral form that diminishes from leftto right and is disposed in anhair duct 89 through which air is forcedfrom left to rig t.

If desired, the spiral configuration of the finned tube 41 in FIGURE 18can be reversed so that the smaller end thereof is first contacted bythe flow of air through the duct 89 from the left.

Because of the simplicity of the construction of the finned tube 41 ofthis invention, it can be readily seen in FIGURES 18 and 19 that thesame is readily adaptable to be formed in spiral form for the intendedpurpose thereof.

Instead of circulating a cooling medium through the finned tube 41 ofthis invention in the manner previously set worth, it is to beunderstood that the same could have a resistance wire 99 passedtherethrough in the manner illustrated in FIGURE 20 which will beinsulated from the interior wall of the hollow tubular member 41 bymagnesium oxide 91 or the like in a conventional manner whereby thefinned tube 41 can perform its heat exchanger function with theelectrical heater element in a conventional manner.

For example, such an electrical heat exchanger element as illustrated inFIGURE 20 can be utilized as a baseboard heater for a home or building92 illustrated in FIGURE 21 and having a baseboard 93 extendingthroughout the internal outer periphery thereof, the baseboard 93comprising a conduit structure in the manner illustrated in FIGURE 22whereby the finned tube 41 of this invention can pass through thebaseboard 93 and be supported therein by suitable brackets 94.

In this manner, either a circulating heating medium can be passedthrough the hollow tubular member 41 in the baseboard 93 or theresistance wire 90 can be passed therethrough whereby the finned tube 41of this invention will provide effective heating for the house orbuilding 92 in a manner conventional in the art.

If desired, the finned tubular member 41 of this invention can be coiledupon itself in spiral fashion to provide a substantially flat heatexchanger construction for forming a condenser, evaporator, or the likefor space heaters, air conditioning units, dehumidifiers and the like.

For example, reference is made to FIGURES 23 and 24 of this inventionwherein a space heater is generally indicated by the reference numeral95 and has the finned tubular member 41 thereof coiled upon itself toprovide a heat exchanger through which air can be forced by a suitablefan 96 in a conventional manner, the finned tube 41 either having thedesired medium circulated therethrough or having a resistance wiretherein in the manner previously described.

If desired, the finned tube 41 of this invention can be disposed insubstantially coiled cylindrical form in the manner illustrated inFIGURES 26 and 27 and placed in a suitable housing 97 to have air forcedtherethrough by a suitable fan 98, the coiled fin tube 41 of FIGURES 26and 27 being particularly adaptable for domestic refrigerator use or thelike although the same can be utilized in other places where a heatexchanger is desired.

Also, the finned tube 41 of this invention can be interconnected to anaccumulator 99 in the manner illustrated in FIGURE 28 and be coiledabout the accumulator 99 to provide means for transferring heat betweenthe finned tube 41 and the accumulator 99.

In addition, the finned tube 41 of this invention can be utilized in anair conditioning unit or the like in the manner illustrated in FIGURES29 and 30 whereby the finned tube is coiled to form an evaporator 100and a condenser 101, the outlet of the condenser 101 beinginterconnected to the inlet of the evaporator 100 by a suitablecapillary arrangement 102 while the outlet of the evaporator 100 isinterconnected to a condenser 103 having the outlet thereofinterconnected to the inlet of the condenser 101, suitable fans 104- and105 being utilized to respectively direct air across the evaporator 100and condenser 101.

Therefore, it can be seen that the finned tube 41 of this invention canbe formed in a plurality of different shapes to form heat exchangerstructures for particular applications thereof because the finnedconstruction 41 of this invention is readily adaptable to be shaped inthe desired configuration and can be simply and rapidly formed in themanner previously described whereby the overall cost of the heatexchanger constructions of this invention are relatively small whencompared with prior known heat exchanger constructions.

In addition, the heat exchanger constructions of this invention have thespecific advantage of the intimate contact between the primary andsecondary surfaces thereof which is a feature heretofore unobtainable inthe prior art.

While the various heat exchanger constructions of this invention can beutilized for many purposes as set forth above, the finned tubular member41 is readily adaptable for forming a frost-proof evaporator forappliances, such as refrigerators and the like.

For example, reference is now made to FIGURES 31- 33 wherein the finnedtube 41 of this invention is formed into an evaporator of desired designand has a heating element 106 coupled therewith, the heating element 106being adapted to have electrical current periodically passedtherethrough to cause the heating element 106 to heat the finned tube 41to eliminate frost thereon in a conventional defrosting manner.

In particular, the heating element 106 can be coupled to the finned tube41 by suitable clips 107 in the manner illustrated in FIGURE 31.

If desired, the finned tube 41 can have outwardly directed flanges 108integrally extruded with the blank 40 as illustrated in FIGURE 32whereby the integral flanges 108 can be utilized to hold the heatingelement 106 to the finned tube 41 by either being deformed around theheating element 106 or by having the heating element 106 snap-fittedbetween the preformed flanges 108.

Alternately, the heating element 106 can be passed directly through thefinned tube 41 in the manner illustrated in FIGURE 33.

While the apparatus 45 of this invention has been previously describedas having the fins 46 drawn, ironed and stretched by the cooperatingsides 53 of the gear teeth 52 of the gear means 47 and 48, it has beenfound that the flat sides 54 of the gear teeth 52 of the gear means 47and 48 can cooperate together to form the fins 46 on the blank 40 byshearing, drawing, stretching and ironing the flanges 42 of the blank 40in a manner now to be described.

For example, reference is now made to FIGURE 34 wherein the gear means47 and 48 are substantially the same as the gear means 47 and 48 ofFIGURE 8 except that the blank 40 is passed therebetween in such amanner that the meshing gear teeth 52 shear, draw, stretch and iron theflange 42 in an upward direction to form the fins 46 between thecooperating straight surfaces 54 of the gear teeth 52.

It has been found that in the embodiment of FIGURE 34, increasing theoffset relation of the gears 47 and 48 increases the interferencetherebetween to increase the surface areas of the fins 46 over thesurface areas of the parts of the flange 42 from which the respectivefins 46 are made. In addition, this increased interference, and, thus,increased surfaces of the fins 46, can be further enhanced by providinga slight radius 109 on the ends of the sides 54 of the gear teeth 52 ofthe gear means 47 and 48 in the manner illustrated in FIGURE 34.

While the blank 40 has been previously described as being extruded, itis to be understood that the blank 40 could be made by other methods.

For example, the blank 40 could be formed by securing two flat sheetstogether with a longitudinal unsecured area therebetween which can besubsequently expanded to form the tubular portion 41, such as in theUnited States Patents to Long, No. 2,662,273, and to Grenell, No.2,690,002, while leaving integral flanges, similar to flanges 42, whichcan be subsequently formed into the fins 46 by the methods previouslydescribed.

Therefore, it can be seen that not only does this invention provide animproved heat exchanger construction or the like, but also thisinvention provides improved methods and apparatus for making such a heatexchanger construction or the like.

While the form of the invention now preferred has been disclosed asrequired by the statutes, other forms may be used, all coming within thescope of the claims which follow.

What is claimed is:

1. Apparatus for making a heat exchanger from a hollow tubular memberhaving an outwardly directed flange integral therewith, comprising apair of rotatable meshing gear members whose teeth have lands which, ina common meshing zone on their widths, curve gradually inwardly towardthe axis of rotation of their gear member.

2. The apparatus of claim 1 wherein the radius of curvature of saidcurve corresponds to the working depth of said teeth.

3. The apparatus of claim 1 wherein said lands on at least one gearmember are adapted to restrain an edge of a fin divided from saidflange, thereby enabling said fin to be drawn to increase its surfacearea while decreasing its thickness.

4. The apparatus of claim 1 wherein each said land connects the ends ofits tooths leading and trailing surfaces, one of said surfaces beingsubstantially flat and the other being convex near its end.

5. Apparatus for making a heat exchanger from a hollow tubular memberhaving an outwardly directed flange integral therewith, comprising apair of rotatable meshing gear members whose teeth have lands which, ina common meshing zone on their widths, curve gradually inwardly towardthe axis of rotation of their gear member, said teeth on one said gearmember having substantially flat trailing surfaces and leading surfacesconvex near their ends, said teeth on the other said gear member havingsubstantially flat leading surfaces and trailing surfaces convex neartheir ends, the ends of said substantially flat leading surfaces meshingbehind the ends of said substantially flat trailing surfaces, saidconvex leading surfaces meshing behind said convex trailing surfaces,and said gear members being adapted to cooperate in rotation so thatsaid flange in passing through their nip is sheared between shearingedges at the ends of said substantially flat surfaces to form fins withthe radially outer portions of said fins twisted out of alignment withthe original surface of said flange while said curved lands in saidmeshing zone allow at least part of the radially innermost portions ofsaid fins to remain in alignment with said original surface, and so thatsaid convex leading and trailing surfaces cooperate to draw and ironsaid fins therebetween to increase the surface area of said fins whiledecreasing their thickness.

6. The apparatus of claim 5 wherein said gear members are substantiallyidentical.

7. Apparatus for making a heat exchanger from a hollow tubular memberhaving an outwardly directed flange integral therewith, comprising apair of rotatable meshing gear members whose teeth have lands at theirends and are so spaced and shaped as to enable said gear members tocooperate in rotation so that as a fin divided from said flange passesthrough the nip of said gears, a land of one gear member restrains oneedge of said fin and a land of the other gear member restrains the otheredge of said fin, whereby said fin is drawn therebetween to increase itssurface area while decreasing its thickness.

8. The apparatus of claim 7 wherein said land on said other gear memberrestrains said fins said other edge by urging it against the leadingsurface of the said one gear members tooth whose land restrains saidfins said one edge.

9. The apparatus of claim 8 wherein said leading surface of said onegear member and said trailing surface of said other gear member areconvex near their ends and are adapted to iron said fin therebetween.

10. Apparatus for making a heat exchanger from a hollow tubular memberhaving an outwardly directed flange integral therewith, comprising apair of rotatable meshing gear members whose teeth have leading andtrailing surfaces connected by lands at their ends, said teeth on onegear member having substantially flat trailing surfaces and on the othergear member having substantially flat leading surfaces, theintersections of said lands and substantially fiat surfaces constitutingshearing edges, and said leading shearing edges on said other gearmember meshing immediately behind said trailing shearing edges on saidone gear member, whereby the shearing edges of the respective gearmembers are adapted to shear said flange to form fins and said lands areadapted to restrain said fins for drawing to increase their surface areawhile decreasing their thicknesses.

11. Apparatus for making a heat exchanger from a hollow tubular memberhaving an outwardly directed planar flange integral therewith,comprising a pair of rotatable meshing gear members with teeth spacedand shaped to cooperate in rotation so that said flange in passingthrough their nip is divided to form fins, and the radially outerportions of said fins are twisted from the plane of said flange anddrawn and ironed so as to increase their surface area while decreasingtheir thicknesses.

12. The apparatus of claim 11 whose teeth are shaped so as to allow theradially innermost portions of the fins to remain in said plane.

13. Apparatus for making a heat exchanger (60) from a hollow tubularmember (41) having an outwardly directed planar flange (42) integraltherewith, comprising a pair of rotatable meshing gear members (47, 48)whose teeth (52) have leading and trailing surfaces (53, 53' and 54, 54)connected by lands (55) at their ends, said lands (55) in a commonmeshing zone (59a) along their widths curving gradually inwardly towardthe axis of r0- tation of their gear member (47 or 48), said teeth (52)on one said gear member (48) having substantially flat trailing surfaces(54) and leading surfaces (53) convex near their ends, said teeth (52)on the other gear member (47) having substantially flat leading surfaces(53') and trailing surfaces (54') convex near their ends (55), theintersections of said lands (55) and said substantially flat surfaces(54, 53) constituting shearing edges (56, 56), said leading shearingedges (56) on said other gear member (47) meshing immediately behindsaid trailing shearing edges (56) on said one gear member (48), saidconvex leading surfaces (53) meshing behind said convex trailingsurfaces (54'), and said gear members (47, 48) being adapted tocooperate in rotation so that said flange (42) in passing through theirnip is sheared between said shearing edges (56, 56') of the respectivegear members (48, 47) to form fins (46a) with the radially outermostportions of said fins (46a) twisted out of alignment with the originalplane of said flange (42) while said curved lands (55) in said meshingzone (59a) allow at least part of the radially innermost portions ofsaid fins (46a) to remain in said original plane, and so that a land(55) of said one gear member (48) restrains one edge of a said fin (46a,46b) and a land (55) of said other gear member (47) restrains the otheredge of said fin (46a, 46b) against the leading surface (53) of the saidone gear members (48) tooth (52) whose land (55) restrains said fins(46a, 46b) said one edge, whereby said fin (46a, 46b) is drawntherebetween and ironed between a said convex trailing surface (54') andthe said convex leading surface (53) meshing therebehind, therebyincreasing the surface area of said fin (46a, 46b, 46) while decreasingits thickness.

14. Apparatus for making a heat exchanger from a hollow tubular memberhaving an outwardly directed flange integral therewith, comprising apair of rotatable gear members with radially extending teeth meshing todefine a working depth substantially greater than the thickness of atooth at the working depth boundary nearest the root of said tooth, saidteeth on one gear member having leading surfaces convex near their endsand on the other gear member having trailing surfaces convex near theirends, said leading surfaces meshing behind and being adapted tocooperate with said trailing surfaces during rotation of said gearmembers so that while said surfaces are adjacent each other there issubstantial relative traversing movement therebetween.

15'. The apparatus of claim 14 wherein the trailing surfaces on theteeth of said one gear member and the leading surfaces of the teeth ofsaid other gear member are substantially flat.

16. The apparatus of claim 14 wherein the trailing surfaces of the teethof said one gear member and the leading surfaces of the teeth of saidother gear member terminate in shearing edges.

17. Apparatus for making a heat exchanger from a hollow tubular memberhaving an outwardly directed flange integral therewith, comprising apair of rotatable meshing gear members with radially extending teethwhich on one gear member have trailing surfaces terminating in shearingedges and leading surfaces convex near their ends, and on the other gearmember having leading surfaces terminating in shearing edges andtrailing surfaces convex near their ends, said leading shearing edgesmeshing immediately behind said trailing shearing edges and beingadapted to cooperate therewith to shear said flange to form fins, andsaid leading convex surfaces meshing behind said trailing convexsurfaces and being adapted to cooperate therewith to deform said fins.

18. The apparatus of claim 17 wherein said surfaces terminating inshearing edges are substantially flat.

19. The apparatus of claim 17 wherein the deforming of said finsincludes drawing and ironing to increase their surface area whiledecreasing their thicknesses.

20. Apparatus for making, from a hollow tubular member having anoutwardly directed flange integral therewith, a heat exchanger havingdrawn fins sheared and twisted from said flange, said apparatuscomprising a pair of rotatable members with radially extending teeth, atooth on one gear member having a rearward shearing edge and a forwardsurface convex near its end and a tooth on the other gear member havinga forward shearing edge and a rearward surface convex near its end, saidgear members being adapted to cooperate in rotation so that said flangein passing forwardly between their converging teeth is sheared betweensaid shearing edges to form fins and the radially outermost portions ofsaid fins are twisted by said convex forward and rearward surfaces outof alignment with the original surface of said flange, leaving at leastpart of the radially innermost portions of said fins to remain inalignment with said original surface.

21. The apparatus of claim 20 wherein said forward and rearward surfacesof each said tooth curve toward each other in a region where said toothis adapted to shear the radially innermost portion of said flange.

22. The apparatus of claim 20 wherein the intersection of each toothsurface with the axis of rotation of its member is a curve in a regionwhere said tooth is adapted to shear the radially innermost portion ofsaid flange.

References Cited UNITED STATES PATENTS 2,596,997 5/1952 Harter 72--1862,963,779 12/1960 Mosgard-Jensen 29157 3,191,418 6/1965 Modine 721961,932,610 10/1933 Tilley 184 2,347,957 5/ 1944 McCullough 165172 X2,646,972 7/1953 Schmerd 165--184 2,792,050 5/1957 Edwards 292022,963,779 12/1960 Mosgard-Jensen 165172 X CHARLES W. LANHAM, PrimaryExaminer LOWELL A. LARSON, Assistant Examiner US. Cl. X.R.

